Spiral piston-ring.



APPLICATION FILED SEPT. 21, I9I4.

I. FLAMIVIANG.

SPIRAL PISTON RING.

Patented Dec. 21, 1915.

ffy/2 I I /II WMO-M rar JOHN FLAMMAN, OF ST. LOUIS, MISSOURI, ASSIG-NOR T INLAND MACHINE WORKS, 0F ST. LOUIS, MISSOURI, A CORPORATION OF vvMISSO'U'RI.

srInAI'. rIsToN-RING.

To all whom lj nwy concern: p

Be it known that I, JOHN FLAMMANG, a

- citizen of vthe United States,.and a resident ing engines,

of the city off'St. Louisand State of M issouri, have invented new and useful I mprovements in Spiral Piston-Rings, of which the following is a specification.

This invention relates to flexible metallic rings for packing the pistons of reciprocatand consists in a piston ring having the form of a continuous spiral and in the process of making the same. I

= Spiral piston rings as heretoiore oo nstructed have the disadvantage of permitting leakage between the convolutions of the spiral unless it is tightly held between the side walls of the groove in the piston. The object of this invention is to produce a .piston ring which has a tightly coiledspiral, the convolutions of which are retained in contact With each other and With the cyl- Vinder throughout the length of the spiral by the resiliency of the metal of whichrthe ring is made.

Further objects of the invention will appear from the following description of the piston ring andthe process of making the same illustrated in the accompanymgdraw- 1n s. f

' igln the drawings, in which like characters designate the samenp'arts in the several views, -Figure 1 is a side view of the tubular piece of metal from which the piston rings are formed, showing the /rst operation of cut-` ting aspiral groove partly completed; Fig. 2 -is an `end view of the same; Fig. 3 1s a side view of the end of the completely grooved tubular piece, and of a spiral ring after it has been separated thererom;`Fig. 4 is a' side view of the spiral ring after-,1t

has been finished preparatory to being re-gv wersed'; Fig. 5`is a side view of the same a er being reversed; and Figs. 6 and7 are tively, of the finished piston ring.

a side elevation and an end face view, respec= The plston rmg may be made of Jny suitable elastic material, such as cast iron or` steel. The metal stock is prepared 1n the` form of a tubular blank 11v with its outside diameter slightly greater than the diameter of the cylinder for which the piston ring is intended, and' with its inside diameter .slightly less than the inside .diameter vof the finished ring. This tubular blank may be of ay convenient length suilicie'nt to form spe'cicatio of Letters Patent.

lutions.

` Patented 1366.21, 1915.l

Application led September 21, 1914. Serial 110.862,692.

chine, and its periphery is. formed with a spiral groove l2 of Ias manypturns as the number of convolutions which it is desired that the pistonring shall have. The depth of this groove is slightly greater than the .thickness of the finished ring. The spiral as the spiral grooves, but if desired these grooves may be made deeper so as to sever the tubular blank into a series of open spiral coils. J Next, the tubular blank 11 is bored out to approximately the inside diameter which is desired for the nished piston ring. Thls operation cuts away the metal at the bottoms of the grooves 13 and the inner peuseveral piston rings. The tubular blank ismounted' in a lathe or other suitable mariphery of the spiral ribs 14 and divides up theptubular blank into a number of separate open spiral coilsV 15. In Fig. 3 the right hand spiral coil 15 has been bored out and separated from the blank'll. -About one turn from each end of the spiral, diametril cally opposite the points where the Width of the helical convolutions starts to become narrower, or taperoiii, shallow notches 16 are led on the inner side of the end convo- These notches extend for about one quarter of a turn toward each other and run f out gradually into the helical side faces of the coil. The ends 17 .of the spiral coil are led olf @square at their extremities, and are bent outwardly at the "points where theyy start to taper so that the outer face" of the tapered portion follows a'true helical curve The spiral coil15 is inverted or turned inside out by passing each convolution progressively from one endV 17 through or over the remainihg convolutions and continuing .the operation until all'of the convolutions have been passed through or over the undisturbed-portion of thegcoil.` This operation changes the Ycoils from a right hand spiral tension against separating (from those adja- Y cent thereto, as shown in Fig. 5. The f o'rce tending-tohold the convolutions in contact ,Llepends'upon the elasticity of the material,`

the 'diameter 'of the coil, and the ywidth of the rspace between the open coils as origi nally made.

The closed coil 18 constitutes an annular `=handhaving a helical cut extending vfrom end face to end face. .The end faces of the coil or band 18 are squared off by'means of suitable tools,` forming a ring 19 having,

' parallel end faces, as shown inFig. 6. The'l end faces and the'periphery of the ring may be ground by the usual methods of grinding piston rings of ordinary form.

The length of the v lo1-1g'it-udinal notches 16 in ythe end faces is suiicient to enable the ends of the spiral to screw around when the ring is coinpressedinto a cylinder, and when` i compressed into a cylinder the gap between the ends of the spiral and lthe shoulders at thefend of the notches -of they adjacent coils will be very small.

It is evident from the preceding descrip* tion that changes inthe dimensions of the spiral Acanv4 be made tosuit the requirements of the uses for which the rings are intended. For example, the resiliency 'of the 'springy can be increased and the'pressure'exerted thereby against the cylinder .correspondingly decreased by increasingthe number of convolutions; and lconversely,i the ring can. be made stiil'e'r and its pressure against the wall of the cylinder 'thereby increased by reducing the number of-convolutions.- Alsop the cross-sectional dimensions vof 'the coils can be varied to increase lthe strength and: stillness of the ring, and'vice versa, aswwill be apparent to .persons having a knowledge of engine design.

The invention is not restricted to the pre- `cise method of manufacture shownv and described, and no claim forthe method is made helix yof elastic material in spring contact axially. l 2. Affpist' olutions arranged i n the form of la helix, adjacent con-v volutioris being in contact throughout -their lengthl and subjected .to vinternal stresses tending to retain them'in contact.

3. A11 elastic piston ring of annular form having parallel sides, said ring being'split circumiferen'tia-llyI on a helical curve, the

.lapping portions of saidl ring being held by their own resiliency in close contact with each other throughout their length.

4.v An elastic piston ring oit/annular form, i having concentric inner and outer cylindrical surfaces yand parallel sides, said ring being split lengthwise from side to side along a helical curve, the lapping prtions of said ring being held by theirown resiliency in close contact with `each other throughout-their length. y

5. An elastic piston ring of annular form having parallel sides, said ring being split lengthwise between points diametrically opposed, the lapping `portions of said ring having tapLered ends and-bein' /held by their ring of.- elastic xmaterial conj s istingfof .a pluralityn of c v own resili ncy in closevcon act with 'each l other throughout their length.

" `lsiglata at st.. Louis, M0., this 19th daysf September, 1914. l A JOHN FLAMMANG. In the'presence of- .'A. MQ, :[-IoLcoisrns M. A; S :|s[EL'ro1\r.'A 

